textproc/R-cran-readr: Update to 2.0.0

- Update to 2.0.0
- Change LICENSE to MIT

Remove # $FreeBSD$ from Makefiles.

- Update to 1.4.0

math/R: Update to version 4.0.0

Upstream changes:
https://stat.ethz.ch/pipermail/r-announce/2020/000653.html

Also bump PORTREVISION of ports that depend on math/R.

Submitted by:	wen (in part)
Reviewed by:	jwb, Rainer Hurling <rhurlin@gwdg.de>, thierry
Differential Revision:	https://reviews.freebsd.org/D24572

Bump PORTREVISION for ports depending on the canonical version of GCC
as defined in Mk/bsd.default-versions.mk which has moved from GCC 8.3
to GCC 9.1 under most circumstances now after revision 507371.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, everything INDEX-11 shows with a dependency on lang/gcc9 now.

PR:		238330

- Update to 1.3.1

Bump PORTREVISION for ports depending on the canonical version of GCC
defined via Mk/bsd.default-versions.mk which has moved from GCC 7.4 t
GCC 8.2 under most circumstances.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, as a double check, everything INDEX-11 showed depending on lang/gcc7.

PR:		231590

Bump PORTREVISIONs of all users of math/mpc that we just updated to
version 1.1.0 (via revision 464079).

- Add new port: textproc/R-cran-readr

  The goal of 'readr' is to provide a fast and friendly way to read
  rectangular data (like 'csv', 'tsv', and 'fwf'). It is designed to
  flexibly parse many types of data found in the wild, while still
  cleanly failing when data unexpectedly changes.

  WWW: https://cran.r-project.org/web/packages/readr/